# Tutorial: Subtracting numbers using PHP.

This is a beginners tutorial on how to do basic subtraction in PHP.

The aim of this tutorial is to help developers who are completely new to the language.

## Simple subtraction.

To subtract numbers in PHP, we can use the Subtraction Arithmetic Operator. Take a look at the following example.

//Subtract 2 from 20.
echo 20 - 2;

In the PHP code above, we subtracted 2 from 20. If you run the above code, the number 18 will be printed out onto the page. This is because 20 minus 2 is 18.

## Assigning the result to a variable.

If you want to assign the result of your subtraction arithmetic to a PHP variable, you can do something like this.

//Subtract 10 from 30 and assign the
//result to a variable called \$answer.

//You can then print out the variable \$answer

In the example above, we subtracted 10 from 30 and assigned the result to a PHP variable called \$answer.

If you print the \$answer variable out onto the page, you will see the number 20. That is because 30 minus 10 is 20.

It is important to note that in this case, our \$answer variable will be an integer. This is because the numbers involved in our subtraction arithmetic were both integers.

## Subtracting variables.

You can also do something like this.

//Create the larger number.
\$a = 40;

//Create the smaller number.
\$b = 25;

//Do the subtraction and assign the result to a variable

//Print the answer out onto the page.

In the code above, we created two variables containing integer numbers and then subtracted them.

## Negative numbers.

If you subtract a larger number from a smaller number, you will end up with a minus figure.

//Our first number.
\$a = 40;

//Our second number.
\$b = 50;

//Do the subtraction.
echo \$a - \$b;

If you run the code above, you will see that the number -10 is printed out onto the page. This is because if you subtract 50 from 40, the result is minus 10.

## Decimal numbers.

Up until this point, we have only been dealing with integers. However, what happens if we use a decimal number?

<?php

//Our first number.
\$a = 10.5;

//Our second number.
\$b = 5;

//Do the subtraction.
\$result = \$a - \$b;

//Print the result.
echo \$result;

The code above will print out the number 5.5. This is because 10.5 minus 5 is equal to 5.5.

Note that in this case, the \$result variable will be a float value. This is because one of the values used in our arithmetic was a float variable (10.5).

## Subtract from the result.

If you store the result of your subtraction in a PHP variable, you can subtract even further.

//Our first number.
\$a = 10;

//Our second number.
\$b = 5;

//Do the subtraction and assign it to a variable called \$result.
\$result = \$a - \$b;

//Print out the \$result variable.
echo \$result . '<br>';

//Subtract 3 from the \$result.
\$result = \$result - 3;

//Print out the \$result variable again.
echo \$result . '<br>';

The PHP code above will print out the numbers 5 and 2. This is because 10 minus 5 gives us 5. Then, we subtracted 3 from 5, which gave us 2.